Performance Study Of Perovskite Solar Cells Based On SnO₂ And ZnO Electron Transport Layers And Ionic Liquids

Perovskite solar cells（PSCs）have been developing at a rapid rate.In just over ten years,the photoelectric conversion efficiency（PCE）of PSCs has grown from an initial 3.8%to a current 25.7%.It was almost as high as the crystalline silicon solar cells that have been developed over the last 60 years.At present,the two major research hotspots of PSCs are to improve PCE and stability.Therefore,it is important to produce high performance perovskite films and electron transport layers（ETL）.Ionic liquids（ILs）play an important role in the preparation of higher performance perovskite films due to their low saturation vapour pressure,high ionic conductivity and low toxicity.The research contents and innovations are as follows.（1）Based on SnO₂ ETL,PSCs were prepared by one-step method.MAAc-based PSCs were prepared DMF and DMSO as perovskite precursor solvent.In particular,the perovskite layer was prepared at room temperature without the use of an anti-solvent.The effect of the concentration of precursors（0.6 mol/L,0.8 mol/L,1.0 mol/L and 1.2 mol/L）on the photovoltaic performance of perovskite films and ILs-PSCs was investigated.The effect of adding different amounts of DMF 2%,5%and 10%)to the solution of perovskite precursors on the performance of perovskite films and cells was also investigated.Finally,the effect of MAAc addition of 5%DMF and DMF mixed with DMSO as a solvent for perovskite precursors on PSCs was compared.The results show that the size and crystallinity of perovskite grains can be regulated by varying the concentration of the perovskite precur sor solution.The best cell performance was achieved when the precursor solution of perovskite was at a concentration of 1.0 mol/L.The cell had a PCE of 11.09%,an open-circuit voltage(V_oc)of 1.13 V,a short-circuit current density(J_sc)of 15.86 m A/cm~2 and a fill factor（FF）of 63.80%.When 5%DMF was added to the perovskite precursor solution based on MAAc solvent,the PCE of the cell was higher and the stability was better than that of the cell prepared with DMF and DMSO solvent as perovskite precursor solvent.The PCE increased from 11.83%to 12.32%,V_oc was 1.12 V,J_scwas 17.57 m A/cm~2 and FF is 62.56%.（2）Butylamine hydrochloride（BACl）as an interfacial modification material between SnO₂ ETL and perovskite layers in PSCs.The effect of BACl modifi cation at different concentrations（5 mg/m L,10 mg/m L and 15 mg/m L）on the performance of SnO₂ films and PSCs was investigated.The results showed that the cell performance is optimal at a BACl concentration of 10 mg/m L.After modification with this concentration of BACl,the wettability of the perovskite precursor solution on the ETL was improved and the concentration of defects in the film was reduced.The device’s PCE has improved by 30%,from 11.68%to 15.23%,with a V_oc of1.11V,J_sc of 18.42 m A/cm~2 and FF of 74.67%.（3）Based on ZnO ETL,PSCs were prepared by one-step method.The effect of different temperatures（50°C,100°C and 200°C）and different amounts of ammonia（50μL,100μL and 200μL）on the photovoltaic performance of ZnO ETL was investigated.The results showed that the cell performed best at a treatment temperature of 100°C and an ammonia dosage of 100μL,with a PCE of 10.26%,V_oc of 0.98 V,J_sc of 18.27 m A/cm~2 and FF of 57.51.It was shown that a small amount of N element was incorporated into the ZnO film after ammonia treatment,which reduced the V_O defects of the film,and the electron mobility of the ZnO film increased from 3.33×10~3 to 9.92×10~3 cm~2/V-S and the resistivity decreased from1.43×10~1Ω·cm to 1.78×10^-2Ω·cm.